The amputation is because of T2, not 1, isn't it? At least I don't remember hearing about it in relation to T1, just T2.
For T2 there already is a quite reliable solution: high-fat animal-based ketogenic diet. Though I don't think it can prevent amputation if it's too late. Frankly, I don't remember seeing anyone fail to reverse their T2 on a great diet. Some might need to go all the way to carnivore though.
nostr:nprofile1qqstzt0wugc7sklvr8e7fcl7ukyn63ym3ns4nmf2mnk0vqnz4l9x65qpp4mhxue69uhkummn9ekx7mqpr4mhxue69uhkummnw3ezumtfv3jxc6twvuhx67tydeeju6nsqythwumn8ghj7mn0wd68ytn5dacx2arg9e5kuen0te28kw and nostr:nprofile1qqs28n3mz7xmqvx9hhxa6x48ex53ylktzlck7ld27hvzz6rqkavg60qpz4mhxue69uhkummnw3ezummcw3ezuer9wchs8xlna5 make content here on nostr about these things if you're interested.
Either way good luck to you and your family!